[ntp:questions] Re: ntpd not listening on port 123

Per Hedeland per at hedeland.org
Fri Jan 7 10:36:06 UTC 2005

In article <uN2dna5YVe8AJEDcRVn-2w at comcast.com> "Richard B. Gilbert"
<rgilbert88 at comcast.net> writes:

>Yes, you missed something!!   NTP uses UDP not TCP.  You may have missed 
>something else as well since my Solaris system does not show anything 
>listening on port 123 either.  My Unix/network skills are not yet good 
>enough to explain why not but ntpd is clearly working so I'm not worried 
>about it.

It's just that LISTEN is basically a TCP state - UDP sockets aren't
generally considered to have such a state, and so an "UDP listener"
doesn't show up as LISTEN. From a Solaris 8 box:

$ netstat -an | grep 123
      *.123                                 Idle                               Idle                               Idle
      *.123                                 Idle

(There is an "UDP: IPv4" header that the grep takes out.)

FreeBSD 5.3:

$ netstat -an | grep 123
udp4       0      0          *.*                    
udp4       0      0           *.*                    
udp4       0      0  *.123                  *.*                    

--Per Hedeland
per at hedeland.org

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